The present invention relates to an apparatus for removing organic contaminants dissolved in waste water by means of an adsorber filled with active carbon and passing in downward direction therethrough, whereas the waste water flows in counter current direction to the carbon through the adsorber.
In such apparatus for purification of waste water by adsorption of the organic contaminants dissolved therein, a uniform distribution of the waste water through the cross-section of the adsorber, as well as a parallel flow of the active carbon laden with the contaminants, is necessary.
To bind organic contaminants dissolved in waste water by adsorption to active carbon to thereby purify the waste water is well known in the art. Usually, the adsorbed contaminants are again removed from the active carbon by thermally treating the latter, whereafter the active carbon will again be used for purifying waste water. While the reversibly bound contaminants may be desorbed strictly by raising the temperature, the irreversibly bound contaminants must be removed by partial gasification of the active carbon. The loss of active carbon resulting thereby from the reaction of the gasification means with the active carbon may be in the order of 5 to 15 percent for each regeneration. The amount of loss of active carbon of course increases during purification of industrial waste water since due to the high percentage of carbon containing contaminants the loading of the active carbon proceeds very fast so that repeated regeneration of the active carbon is necessary.
In a process in which the laden active carbon is continuously discharged from the adsorber, it is necessary to hold the volume of the stream of laden active carbon between adsorber and regenerator as small as possible to thereby reduce the loss of active carbon. This can be accomplished when the active carbon is discharged from the adsorber in a state in which it is laden to the maximum with adsorbed contaminants.